The triple terror bombing of Israeli tourists in Egypt overnight Friday may signal the opening of a new front in al-Qaeda's battle to supplant pro-Western regimes in the Arab world. Or rather, the reopening of an old one. It is possible, of course, that the near-simultaneous attacks that killed more than 30 people, most of them Israeli tourists at the Hilton Hotel in Taba, and at the Red Sea resorts of Nuweiba and Ras al-Sultan, could be the work of others. Radical Palestinian groups would certainly make any list of possible suspects, particularly given the target. Hamas has long promised to hit back for Israel's systematic elimination of much of its leadership cadre, and with Israel''s military actions impeding suicide bombers and rocket attacks, Israeli holidaymakers in nearby Egypt certainly make a tempting soft target. Even the headline target location, Taba, has symbolic significance  as the site of intense last-ditch negotiations four months after the aborted Camp David talks, the town has lent its name to the most comprehensive draft two-state peace agreement negotiated to date between Israelis and Palestinians. And that's a deal long rejected by Palestinian radicals.

But launching an attack on Egyptian soil would mark a dramatic, and risky strategic shift even for Hamas or Palestinian Islamic Jihad, while groupings associated with Yasser Arafat's Fatah movement would likely be mindful of its strategic relationship with the Egyptian leadership. But Cairo maintains cordial relations even with the Palestinian Islamists, often mediating in cease-fire talks among the three groups. The consequences for any Palestinian group of challenging President Hosni Mubarak in this way would likely be immediate and painful, diminishing their motive.

A second set of suspects would be Egyptian Islamist groups such as Islamic Jihad and the Gama'a Islamiya. Both groups broke away from the more moderate Muslim Brotherhood to wage a terror war against Mubarak and his predecessor, President Anwar Sadat. For much of the 1990s, they waged a terror campaign at home, culminating in the massacre of 57 tourists at Luxor in 1997 by the Gama'a. But a harsh crackdown saw much of its leadership imprisoned, and from their prison cells they have renounced violence and declared an official cease-fire. The Islamic Jihad group, headed by Ayman Zawahiri, rejected the cease-fire; they had already made common cause with Osama bin Laden in Afghanistan and had, to all practical purposes, essentially merged their organizations. That alone would be enough to make Egyptian Islamic Jihad the more likely suspect  which is the same as saying al-Qaeda, given the 1998 merger which formalized Zawahiri's status as Bin Laden's Number 2. Indeed, many al-Qaeda watches argue that far from simply subordinating themselves to the leadership of the charismatic Saudi, the veterans of Egyptian Islamic Jihad who made common cause with Bin Laden in Afghanistan during the 1990s actually became the operational high command of the al-Qaeda leadership.

Triple bombing in different locations of a similar symbolic nature is certainly an al-Qaeda operational signature. A taped message from Zawahiri broadcast by Al Jazeera on October 1 put Egypt at the top of the list of countries in which Muslims were urged to begin "preemptive" acts of resistance against the U.S. and its allies, including Israel. And Israeli officials indicated Friday that they suspect Qaeda involvement. If the attacks were, in fact, authored by Egyptian Qaeda operatives, they'd mark a bloody return home for some of the world's most hardened Islamist terrorists. Peace between Egypt and Israel was the issue over which Egyptian Islamic Jihad announced itself to the world, through the 1981 assassination of President Anwar Sadat. A combination of harsh repression and a conscious decision to "export" the problem by shipping off radical Islamists by the planeload to Afghanistan to wage jihad against the Soviets blunted much of Islamic Jihad's impact inside Egypt, although both Jihad and the Gama'a took up a more bloody domestic campaign in the 1990s was eventually crushed by Mubarak's secret police, leaving the radicals mostly either in prison or dispersed. But the Egyptians who honed their skills in Afghanistan made their mark elsewhere, whether in attacking Egyptian diplomats and leaders in Pakistan and Ethiopia, and by their participation in key Qaeda operations.

Reopening the "home" front may be a timely strategic decision by Zawahiri and his followers, in the way that the Qaeda movement has done in Saudi Arabia. The long-term political weakness of Mubarak's autocracy, buffeted by the mounting demographic pressure of a stagnant economy unable to produce jobs for growing numbers of its youth, has been exacerbated by the Palestinian Intifada and the U.S. invasion of Iraq. Even if they don't necessarily accept the Islamist charge that Mubarak is carrying water for Israel, many Egyptians perceive their government as unable to stand up to Israel and the U.S. on behalf of the Palsetinians and Iraqis. By killing Israelis on Egyptian soil, the perpetrators of the Red Sea terror attacks look to exacerbate the crisis facing Mubarak. The attack highlights the common interest between Mubarak's regime, Israel and the U.S. in the face of an onslaught by international jihadis  but that's a unity with which Mubarak may not be entirely comfortable, right now, given the depth of hostility among his own population towards both the Americans and the Israelis. The perpetrators of the latest attack could be betting that the groundswell of hostility towards the U.S. and Israel among ordinary Egyptians enraged by events in Gaza and Iraq would make it more difficult for the Mubarak regime to sustain a crackdown.

Mubarak has faced down such challenges before, and there's no immediate threat to his regime. But the autocrat is 76 years old, and rumors of ill health have swirled through the Arab media in recent years. And there's no obvious successor yet in place or even a clear process for selecting one in a political system that has, since the early 1950s, been dominated by the security establishment, and in which the outlawed Muslim Brotherhood remains, by most estimates, the most popular opposition group. The bombers have certainly turned up the heat on Egypt at a moment when the system's structural weakness are under strain. The effects of the carnage along the Red Sea may eventually be felt by many more than just the families of the victims.